In mice and in humans, treatment with the second generation antipsychotic drug olanzapine (OLZ) produces excessive weight gain, adiposity and secondary metabolic complications, including loss of glucose and insulin homeostasis. In mice consuming a high fat (HF) diet, a similar phenotype develops, which is inhibited by the analgesic acetaminophen (APAP) and by the antioxidant tetrahydroindenoindole (THII). Therefore, we examined the ability of APAP and THII to prevent metabolic changes in mice receiving OLZ.
Design and Measurement
C57BL/6J mice received either a normal diet or a high fat diet, and were administered OLZ (3 mg/kg body weight/d), alone or with APAP (35 mg/kg body weight/d) or THII (4.5 mg/kg body weight), for 10 weeks. Parameters of body composition and metabolism, including glucose and insulin homeostasis and oxidative stress, were examined.
OLZ treatment doubled the HF diet-induced increases in body weight and percent body fat. These increases were partially prevented by both APAP and THII, although food consumption was constant in all groups. The THII protection was associated with an increase in whole body and mitochondrial respiration. OLZ also exacerbated, and both APAP and THII prevented, HF diet-induced loss of glucose tolerance and insulin resistance. Since increased body fat promotes insulin resistance by a pathway involving oxidative stress, we evaluated production of reactive oxygen and lipid peroxidation in white adipose tissue (WAT). HF diet caused an increase in lipid peroxidation, NADPH-dependent O2 uptake and H2O2 production, which were further exacerbated by OLZ. APAP, THII, and the NADPH oxidase inhibitor, diphenyleneiodonium chloride (DPI) each abolished oxidative stress in WAT.
We conclude that both APAP and THII intervene in the development of obesity and metabolic complications associated with OLZ treatment.